The present invention relates to a calculus crushing apparatus for crushing a calculus produced in a body cavity.
Calculi produced in internal organs, such as the bile duct, bladder, etc., greatly endanger the health of, and cause great pain to, patients.
To rid patients of their calculi, a method is conventionally used in which a calculus crushing apparatus is inserted into the body with the aid of an endoscope, whereby calculi produced in the body are crushed and eliminated from the body or extracted whole.
In one such prior art crushing apparatus, a basket formed of a plurality of elastic wires and adapted to seize foreign substances is fixed to the distal end of an operating wire, and the operating wire, along with the basket thereon, is inserted into a flexible sheath which has a rigid portion at its distal end, and is caused to advance or retreat from behind the rear end of the sheath, thereby extending or contracting the basket. After a calculus is seized by the basket projected from the distal end of the flexible sheath, the basket is drawn into the sheath to be collapsed by operating the operating wire. Thus, the calculus in the basket is crushed into small pieces.
In the calculus crushing apparatus of this type, as disclosed in, e.g., Japanese Utility Model Disclosure No. 55-34810, the operating wire for operating the basket is controlled by a slide mechanism. When drawing in the operating wire by the use of such a slide mechanism, there is no problem in regards to the operation before the crushing of the calculus. After the calculus is crushed by the contracted basket, however, the operating wire is released from resistance thereon for an instant, so that the basket will be quickly drawn into the flexible sheath. When this happens, fine pieces of the crushed calculus forcibly scatter, causing prossible injury to the inner wall of the body cavity.